Linux: Chat tab reported as unavailable, phone chats don't show up in Claude Desktop (beta)

Summary

On Linux, Claude Desktop (beta) reports the Chat tab as unavailable, so conversations started on the phone/web never show up in the desktop app. The same account shows all its chats on claude.ai in a browser.

Environment

• Claude Desktop 2.9939.4 (Electron 44.4.3), x86_64
• Gentoo Linux, kernel 6.18.50, KDE Plasma on Wayland
• Installed from the official .deb in the apt repo (downloads.claude.ai/claude-desktop/apt/stable), unpacked manually with ar/tar because Gentoo has no dpkg. I know Gentoo is not a supported distribution; I'm reporting it in case the cause is not distro-specific.
• Account: Pro subscription (single account)
• Sign-in storage works: KDE Wallet is running and main.log shows [safeStorage] kwalletd pre-flight (kwalletd6): has-wallet.

What happens

• The sidebar only shows "New chat", "Artifacts" and "Customize". There is no chat list and no history.
• Chats created on the phone do not appear. In a browser on claude.ai the same account lists them normally.
• logs/supported-features-info.json contains:
• "chatTab": {"status": "unavailable"}
• "chatCodeExecution": {"status": "unavailable"}
• "chatIn3p": {"status": "supported"}

No reason is given for unavailable.

• The Code tab works: it recovered 79 existing CLI sessions from ~/.claude.
• main.log shows no network or authentication errors. https://claude.ai loads fine (proxy ... resolved (direct)).

Expected

The docs (desktop-linux) say the Linux app gives "the same Chat, Cowork, and Claude Code experience as on macOS and Windows" and list no Chat limitation among the beta gaps.

Already tried

• Reproduces on the previous version (1.52386.3) and again on 2.9939.4 with a completely fresh ~/.config/Claude, after signing in again.

Questions

• What decides whether chatTab is available on Linux? Is it a server-side rollout/flag, a platform check, or something local (e.g. a missing dependency or the unsupported distro)?
• Could the status include a reason so users can tell?